Spring Boot

How I implemented PostgreSQL outbox polling with SKIP LOCKED, explicit message states, and bounded retries, and where hard-crash recovery needs an additional policy.

How I implemented a Kafka notification consumer with CAS state transitions, separate data and infrastructure error paths, and deliberate acknowledgment ordering.

Why a notification pipeline used one PostgreSQL transaction for business data and event intent, then separate Kafka publishing and consuming workers—and what that structure does not guarantee.

A single shared queue worked with one WebSocket server, but competing consumers sent some messages to servers that did not own the target session. This case study explains the failure and the routing topology that fixed it.

A real-time service created a new RabbitMQ connection and channel for every publish. This case study explains why that lifecycle was wasteful, how I moved ownership to the application, and what to verify when resources are reused.